The regulation of the naturally occurring neurotransmitter serotonin in the central nervous system (CNS) can be assessed indirectly by measuring physiological and behavioral responses following the administration of a serotonergic medication. The purpose of this pilot study is to assess neuroendocrine responses and eating behavior following single-dose administration of the recently approved serotonergic antidepressant medication citalopram (Celexa) (TM).